1. LCAS scenario Ethernetclient Domain 2 SDH network UNI UNI Domain 1 SDH network Domain 3 SDH network Ethernetclients Ethernetclient

2. LCAS scenario • (Multi-domain) SDH transport network with GFP/VCAT/LCAS capabilities (at least in the edge-nodes) supporting ethernet clients both “smart” (i.e. routers) and “dumb” (i.e. switches) devices • Dynamic allocation of VCs to efficiently transport ethernet traffic (up to 2 VC-3 for fast-ethernet and up to 21 VC-3 for gigabit-ethernet). Different granularities may be used as well. • For “smart” client devices: • UNI with “call bandwidth modification” capabilities • For “dumb” client devices: • An automatic trigger mechanism can be implemented on the edge nodes, monitoring the amount of traffic received from the client device

3. Network services • Use of legacy SDH metro/regional networks for transport of ethernet signals from the access segment to the metro aggregation POP • Interconnecting of geographically distributed ethernet LANs • Interconnecting metro PoPs via a Core (Long Haul) Network

4. Issues • The most interesting feature of LCAS is the capability of dividing the VCG on 2 or more diversely routed paths, thereby allowing higher degree of resilience. This poses several issues: • Call/Connection separation (separate call and connection setup, identification of LSPs belonging to the same Call, traffic descriptors mapping) • Managing resilience requirements (e.g. diversity) • LCAS operation indication • Upstream LCAS procedure triggering • Managing delay skew of different connections (is this really an issue?)